Pumps



Jan. 2s, 1969 C. HUGHES 3,424,096

PUMPS Filed June 2, 1966 Sheet of 2 CELiL HUSHES @a '129m Upea Mtn-legs Jan. 28, 1969 c. HUGHES 3,424,096

PUMPS 'ceciL HUSHES .QH-anne? 'United States Patent 0 36,644/65 U.s. Cl. 10s- 151 Int. cl. F0411 43/02 4 Claims ABSTRACT F THE DISCLOSURE A pump construction in which a casing is divided into three chambers in series by a pair of impulsion members in the Iform of flexible diaphragms clamped at their centres to drive rods. The rods project from the pump casing at mutually remote ends thereof and are reciproca-ble towards and away from each other t-o move the diaphragms in opposition. The sliding bearing of each rod in the casing is protected by a flexible sleeve surrounding the rod and clamped between the rod and the casing. The chambers defined by the diaphragms have similar mean volumes but the casing has tapering ends so that the end chambers to which the drive rods extend are longer than the intermediate chambers. Supporting plates prevent undue exure of each diaphragm during a delivery stroke.

This invention relates to pumps and especially to pumps for the movement of liquids. It is particularly concerned with arrangements in which the pumping effe-ct is achieved by applying a reciprocatory motion to a flexible plate or impulsion member.

An object of the invention is to provide a pump in which a relatively smooth throughput of liquid can be obtained despite the use of a reciprocating drive.

A further object of the invention is to provide a liquid pump that is a-ble to deal satisfactorily with liquids carrying suspended solids.

In a pump according to the invention, at least three chambers are arranged in series in a casing, a dividing member between each successive pair of chambers being formed by a flexible plate and peripheral sealing means 'being provided on the casing inner wall to form seatings for the respective plates, the members being oppositely reciprocable by external drive means to vary the volumes of the chambers and each plate being displaceable from its seating to permit flow from the preceding to the following of its successive chambers.

To handle liquids carrying solids in suspension, it is particularly desirable to keep the flow out of contact with any sliding parts because of the Ipossible abrasive effect of the solid particles. In such cases, each flexible plate may be carried by a rod or like supporting member projecting through a bearing aperture in the casing, the supporting member having a flexible sealing member, such as a tubular sleeve, secured between it and the casing to prevent leakage between the pump chambers and the bearing aperture.

The invention will .be more particularly described with reference to the accompanying drawings wherein:

FIG. l is a side View of a pump according to the invention and FIG. 2 is a sectional view on the line II-II in FIG. l.

Referring to the drawings, the pump comprises a casing 2 formed lby three cast sections, thesections being designated 2a, 2b, 2c. Within the casing, flexible discs 4, 6 can seat upon respective lips formed integrally with the casing sections 2a, 2b to define on their downstream sides sealing faces 8, 10 whereby the casing interior is divided 3,424,096 Patented Jan. 28, 1969 ice into inlet, intermediate and outlet chambers 12, 14, 16, respectively arranged in series between an inlet port 18 and an outlet port 20. The discs are each displaceable upwardly from their seatings so that one-way ow between the inlet and outlet ports can be established.

Each disc 4, 6 is carried by a rod 22 axially guided in bearing tube 24 fixed to the casing by its flange 25, the disc being gripped between the flat supporting faces of upper and lower clamping plates 26, 27 by tightening nut 28 to secure it to the rod. In this construction the two rods are coaxial and the discs 4, 6 and their sealing faces 8, 10 are circular in plan rform.

The ends of the rods 22 project from the casing and transmit the pump drive to the discs 4, 6. The drive comprises an input shaft 30 carrying eccentrics 32 to which connecting rods 34 are journalled. The outer ends of the connecting rods are journalled to respective beams 36 which are carried by lugs 37 of the casing through links 38 and which are in turn journalled to the ends of the rods 22.

The eccentrics are out of phase so that rotation of the shaft 30 lcauses the rods to move op positely to each other. Considered lfrom the mid-position shown in the drawing, such movement will cause the discs 4, 6 to move towards each other (say) initially. The volumes of the inlet and outlet chambers' 12, 16 will then increase and the volume of the intermediate chamber 14 will decrease. This decrease will mean that liquid is forced out of the intermediate chamber and, because of the arrangement of the discs, the disc 4 will be urged more firmly on its seating so that the liquid will be displaced into the outlet chamber, the disc 6 being held olf its seating by the liquid pressure. However, the rate of decrease in volume of the chamber 14 will be approximately double the rate of increase of volume in the outlet chamber so that the liquid displacement from the intermediate chamber gives a net outflow through the pump outlet 2-0.

Liquid in the meantime is being drawn into the inlet chamber. When the movement of the rods reverses, the reduction in volume of the youtlet chamber causes further flow through the outlet 20 since the disc 6 will now be held on its seating by the pressure in the outlet chamber while the increasing volume of the intermediate chamber causes the disc 4 to rise off its seating so that liquid enters from the inlet chamber.

Thus, in both half cycles there is delivery from the pump outlet. In operation, the cycle reversals follow relatively rapidly and by virtue of a number of features of the construction illustrated it is possible to take advantage of the pump ram effect, that is to say, the inertia of the moving liquid column, to increase the rate of flow through the pump.

In particular, it will be noted that a relatively direct path is provided for the flow through the pump since the inlet and outlet 18, 20 are arranged on substantially parallel axes directed generally towards each other and arranged to intersect the areas bounded by their respective adjacent discs 4, 6. The discs, being made of a exible material, are able to respond readily to the existence of suitable conditions to permit the ram effect of the liquid to operate.

The discs 4, 6 are also able to offer a relatively large cross-sectional area for the throughow and in this connection it will be noted that each clam-ping plate 26 has a relatively small outside diameter so that a large area of the disc is unsupported when it is being liexed upwardly away from its seating. On the other hand, each clamping plate 27 has a relatively large diameter to provide ample support for the disc when it is being held in a sealing position against its seating.

A non-return valve 40 is provided at the pump inlet but it is found in practice that this normally remains open due to operation of the ram effect and offers little or no obstruction to the flow entering the pump. It is of use, however, during priming of the pump, i.e. when air is being displaced from the pipelines to raise liquid into the pump. As a further precaution, a non-return valve 41 may also be arranged at the pump outlet.

In order to prevent leakage of liquid out of the chambers or air into the chambers through the working clearances of the rods 22 and their tubes 24, a exible sleeve 42 is secured between each rod and its bearing tube. To this end, collars 44, 46 are provided on the adjacent clamping plate and on the bearing tube respectively, and the sleeve 42 is sealingly clamped on the collars by hose clips 48. It will be noted that the free length of each sleeve 42 has a large radial clearance with the adjacent rod and bearing tube so that it is possible to preclude rubbing of the sleeve during its deformation as the rod reciprocates. Preferably, the sleeves are so mounted that they are unstressed axially when the rods are at the mid-position illustrated. In this way they are subjected to both tension and compression forces and the peak forces experienced are minimised.

It will be noted that since each bearing tube 24 and its rod 22 and associated parts can be assembled together prior to being secured to the pump casing, the sleeves can be secured also to the sub-assemblies in their axially unstressed condition.

By use of the sleeves 42, the pumped medium is kept out of contact with any sliding surfaces of the pump mechanism. The construction is therefore suitable, with an appropriate choice of materials for the interior parts, for pumping chemically active liquids such as oils and acids and also for pumping liquids with high percentages of semi-solids or solids in suspension, such as sewage, grain, gravel and sand. In this connection, the maintenance of ram elect offers a further advantage in giving the suspended material less opportunity to settle out.

The pump as illustrated and described has a relatively robust and simple construction that allows maintenance and the replacement of parts to be performed easily and quickly. As will be appreciated from the explanation of the operation of the pump, it is able to maintain a relatively smooth flow despite the use of a reciprocatory mechanism and it can be employed both under conditions of suction lift or of pressure head.

What I claim and desire to secure by Letters Patent is:

1. A liquid pump comprising in combination, a casing, means within said casing dividing the space therein into three chambers of similar volume and arranged in a series axially of the casing, inlet and outlet ports in the casing at the first and last of said chambers, each dividing means between each successive pair of chambers including a flexible impulsion member and a peripheral seating on the casing inner wall forming a sealing face for the outer region of an upstream of said member, carrier means for each member, each carrier means including a rod, a bearing in the casing slidably receiving said rod to permit its reciprocation axially of the casing, engagement means between an inner end of said rod and said member, the engagement means comprising a pair of clamping plates having planar supporting faces bearing on the member centrally of said peripheral seating, that plate engaging the upstream side of the member providing a substantially larger support area than the plate on the downstream side of the member, and drive means mounted externally of the pump casing to give said carrier means mutually opy posed reciprocations axially of the pump casing to cause a flow through the pump by reciprocation of the impulsion members, the two rods for the respective impulsion members project into the casing from axially remote ends thereof, respective link members mounted externally of the casing being arranged to reciprocate said rods, a common rotary shaft being connected to the link members and forming the drive input to the pump.

I2. A pump according to claim 1 wherein a flexible sealing member in the form of a tubular sleeve surrounds each rod and is sealingly secured at one end to the casing adjacent said bearing and at the other end to the carrier means adjacent the impulsion member whereby the bearing is isolated from the fluid in the pump interior.

3. A pump according to claim 2 wherein each said bearing comprises a transversely extending mounting element forming attachment means to the casing and an axially extending rod-engaging member arranged to sealingly receive at a peripheral region said one end of the exible member, each flexible member thereby being capable of assembly with its carrier means before attachment of the carrier means to the pump casing.

4. A liquid pump comprising, in combination, a casing, dividing means within said casing dening at least three chambers arranged in series, said three serially arranged chambers have similar volumes and the two end ones of said chambers have cross-sectional areas that tape towards their mutually remote ends and are of greater length than their intermediate chamber, each dividing means between a successive pair of chambers including a flexible plate and peripheral sealing means xedly located on the casing inner wall to form a seating for said plate, bearing means in the casing at mutually remote regions thereof, a mounting for each plate being received in said bearing means to be displaceable axially of the casing, the two llexible plates dividing said three serially arranged chambers having their respective mounting means each extending axially through the length of an end one of said three chambers, a flexible sealing sleeve surrounding each said mounting and opposite ends of the sleeve being secured relative to said flexible plate and to the casing to extend substantially the axial length of the chambers, drive means for the pump being operatively connected to said mountings to reciprocate them axially in opposition to each other whereby the volumes of the chambers are varied and each plate is displaced from its seating to permit flow from the preceding of its successive chambers to the following chamber.

References Cited UNITED STATES PATENTS 2,102,797 12/1937 Helmer 103-202 2,278,832 4/1942 Cornelius 230-171 2,833,226 5/1958 De Meux 103-166 3,162,335 12/1964 Kogan et al. 103-148 3,164,100 1/1965 Hughes 103-148 FOREIGN PATENTS 539,247 9/ 1941 Great Britain.

WILLIAM L. FREEH, Primary Examiner. 

